Apparatus for and method of manufacturing a portable heater

ABSTRACT

The present invention relates to and includes an apparatus for use as a heater that may in certain embodiment be a portable heater and methods of manufacturing the same. The various apparatus and methods of the present invention may be of particular use in providing an efficient heater capable of construction with more robust materials. The present invention may provide many advantages including reducing hot spots and extending the useful life of the heater.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to and includes an apparatus for use as aheater that may in certain embodiments be a portable heater and methodsof manufacturing the same. The various apparatus and methods of thepresent invention may be of particular use in providing an efficientheater capable of construction with more robust materials. The presentinvention may provide many advantages including reducing hot spots andextending the useful life of the heater.

2. Description of the Art

Heating is a vital concern. Traditional methods of heating have includedopen fires, fireplaces, Franklin stoves, and radiators. The progress ofinnovation has not ignored the art of heating. Today there are a widevariety of techniques, methods, and apparatus for heating. An example ofsuch a modern apparatus is provided in U.S. Pat. No. 6,470,876, whichdescribes a self-contained portable heater.

In general, heaters attempt to perform the process of heating the airefficiently in a relevant environment. Such an environment may, forexample, be an airport hanger, a warehouse, or even a tent. Many heatingdevices that convert electricity into heat do so by means of theinherent losses of resistive metal (or other conductive) coils. Thesedevices, thus, can consume significant amounts of electricity.Consequently, these approaches may entail considerable problems. Forexample, electricity is difficult to store and transport safely in largequantities. Resultantly, such heaters usually require connection to asource of external electric power. Additionally, because of the quantityof electricity consumed, the cost of operating such heaters is oftensignificant.

Other heaters contain an alternative initial source of energy to beconverted into heat. These may include, for example, kerosene, propane,or other fuel-air devices. These devices may, in certain cases, containcatalysts or carburetors. One concern that arises in this context is thesuitability for breathing of the gasses that are the immediate result ofcombustion (the combustion gasses, which may also include unoxidizedfuel gasses, as well as other gasses such as atmospheric gasses orinhibitor gasses, such as nitrogen). These gasses frequently includelarge quantities of carbon dioxide, as well as significant quantities ofcarbon monoxide. Other gasses and airborne particles may also be foundin the stream of combustion gasses. This stream, therefore, is generallynot considered desirable for direct use as warm breathable air. Instead,the heat from the stream of combustion gasses must be transferredwithout transferring the contamination of the combustion gasses.

To solve the air quality problem described above, a heat exchanger issometimes used to heat “clean” air on one side of the heat exchanger'sboundaries with “combustion gas” on the other side. Although the word“clean” is used to describe this air, it is merely used to distinguishit from the combustion gas, by providing what is envisaged to be asignificant use of such devices as a metonym.

Traditional large portable heaters use thin-wall steel tubes in theconstruction of their heat exchangers. The hot combustion gas in theseheaters flows through these tubes and the clean air flows amongst thetubes. Heat is transferred from the combustion gas inside the tubes tothe tube walls and then from the tube walls to the surrounding airprimarily by forced convection.

Conventional techniques in structuring these tube-based heat exchangersresult in heat exchangers that have certain problems. For example, theymay have hot spots because it is very challenging to create an evenairflow amongst the tubes. These hot spots may lead to prematurefailure, such as by creating cracks that allow the combustion gasses toescape.

In particular, many remote areas that may benefit from a portable heaterare considered environmentally sensitive. Thus, there is a need toprovide a portable heater that is reliable and powerful, yetenvironmentally safe.

SUMMARY OF THE INVENTION

The present invention addresses the problems in the art stated above andprovides certain advantages over the prior art. The present inventionaddresses the problem of bulky storage of electricity or requirementsthat electrical connections be present by, for example, providing a heatexchanger that is capable of operation with fuel-air heat sources. Thisability to use fuel-air sources permits the generation of heat fromreleases of chemical energy by, for example, combustion as opposed tomerely electrochemical reactions and resistive heating techniques.

The present invention also addresses the problem of unbreathablecombustion gasses by permitting the combustion gasses to transfer theirheat without contaminating the clean air. This is accomplished by theuse of a heat exchanger that separates the flow of combustion gasses andclean air, thereby preventing their admixture. Additionally, after muchof the useful heat has been transferred to the clean air, the combustiongasses may be “scrubbed” using conventional filters and techniques toavoid harmful or deleterious effects on release or escape from thesystem. The present invention may be used in a variety of applicationsincluding, for example, to heat a building under construction, to heat atemporary work seat, to provide mobile emergency heat, to heat awarehouse, or to heat an airplane hanger.

The present invention also addresses the problem of uneven flow aroundtubes in a heat exchanger. In the present example, the clean air mayflow smoothly between a pair of plates in the heat exchanger, andparallel to any bends in those plates. Thus, the clean air does notexperience the turbulence found among the tubes. Moreover, as the cleanair is heated, it expands. The expansion of the clean air forces it toapply even greater pressure to the surface of the plates.

The present invention also addresses the problems of hot spots in thesystem. As explained above, the present invention may allow the cleanair to very efficiently and evenly remove heat from the surface of theplates. Because the heat is removed evenly, hotspots and resultingstress fractures or other defects are also avoided.

The present invention may additionally accrue the advantage of a longerlife than prior heaters, because it reduces the incidents of hot spots:a significant cause of failure in heaters. The present invention mayalso permit the use of stainless steel in plate form. The use ofstainless steel may provide the advantage to the system of being rustand corrosion resistant. This advantage may in turn, provide the furtheradvantage of again increasing the longevity of the system.

The present invention may also accrue the advantage of being suitablefor use in very cold conditions. This invention may, for example, beuseful in Alaska, Antarctica, or other arctic and sub-arctic areas. Inparticular, the present invention may be used to provide, for example,700,000 BTU of heat, which may be of particular value in very coldenvironments. Moreover, certain embodiments of the invention may rangein thermal output from about 20,000 BTU to about 10,000,000 BTU.

One embodiment of the present invention may be an apparatus including anenclosure having at least one input and at least one output for a firststream of fluid and at least one input and at least one output for asecond stream of fluid, at least three plates secured within theenclosure, wherein the plates are adapted to prevent physical admixtureof at least two streams of fluid, and wherein the plates are adapted totransfer heat from at least one of the streams to at least one other ofthe streams. In such an embodiment the plates may be arranged in astack. In another such embodiment the stack includes two or moreapproximately parallel plates. In particular, the plates may be arrangedin parallel. Such an arrangement may allow many plates to be somewhatevenly stacked. In a further such embodiment, the stack may be adaptedto permit flow of clean air within a first pair of plates, and to permitthe flow of combustion gas within a pair of plates that includes onlyone of the first pair of plates. Thus, the combustion gasses may bedirected to flow through a pair of plates, thereby heating these plates;meanwhile, clean air may flow across the other side of each of theplates cooling the plates by transferring the heat to the cool air.

In another such embodiment, the stack may be adapted to permit flow ofclean air and combustion gas respectively within alternating pairs ofthe plates in the stack. In a further such embodiment, the plates may bebent in two or more locations. Such a bend may create a washboard effectin the flow of gasses that may be perpendicular to the bend, whileallowing a smooth laminar flow of gasses parallel to the bend. In yetanother such embodiment, the plates may be corrugated. In another suchembodiment, the plates may be bent in a direction orthogonal to the flowof at least one of the two streams of fluid.

In another such embodiment, the plates may comprise a material such asstainless steel, aluminum, galvanized steel, mild steel, aluminizedsteel, or combinations or alloys thereof. One of ordinary skill in theart will recognize that other metals and other materials may be suitedto transfer heat without permitting combustion gasses to mix with cleanair. In yet another such embodiment, the plates may include a platemetal. In a further such embodiment, at least one of the streams mayinclude a stream of combustion gas. In a yet further such embodiment, atleast one of the streams may include a stream of clean air. In anothersuch embodiment, the fluid may include a fluid such as a gas, a plasma,or a liquid. Additionally, although the invention is described in termsof heating a stream of clean air, one of ordinary skill in the art willrecognize that the invention may, for example, be used to cool a firststream of fluid. In this example, the combustion is cooled while theclean air is heated. In still another such embodiment, the streams offluid may be disposed orthogonally to one another.

Another embodiment of the present invention may be an apparatusincluding a fuel source, an air source, a combustion mechanism, acombustion chamber adapted to receive fuel from the fuel source and airfrom the air source, and to contain an operative portion of thecombustion mechanism, a combustion gas channel, wherein the channel mayinclude an enclosed stack of plates, and an exhaust pipe, and whereinthe enclosed stack of plates is adapted to permit the flow of combustiongas between alternating pairs, and clean air between the other pairs.Such an apparatus may be used as a heater. If desired, the clean airmay, after passing through the alternating pairs of plates, be directedaround the combustion chamber. Such an organization may permit the cleanair to obtain additional thermal energy prior to escape from the heaterapparatus.

In another such embodiment, the stack may include two or moreapproximately parallel plates. In a further such embodiment, the platesmay be bent in two or more locations. In yet another embodiment, theplates may be corrugated. In a yet a further embodiment, the plates maybe bent in a direction orthogonal to the flow of at least one of the twostreams of fluid.

In another such embodiment, the plates may comprise a material such as,for example, stainless steel, aluminum, galvanized steel, mild steel,and aluminized steel. In a further such embodiment, the plates mayinclude a plate metal. In yet a further embodiment, at least one of thestreams may include a stream of combustion gas. In yet anotherembodiment, the fluid may include a fluid selected from a groupconsisting of a gas, a plasma, or a liquid. In a still furtherembodiment, the streams of fluid may be disposed orthogonally to oneanother.

Another embodiment of the present invention may be a method includingproviding at least three plates, disposing the plates to accommodate theintra-plate flow of at least two streams of fluid, adapting the platesto prevent physical admixture of at least two of the streams of fluid,and adapting the plates to transfer heat from at least one of thestreams to at least one other of the streams.

In another such embodiment, the step of disposing may include arrangingthe plates in a stack. In a further such embodiment, the step ofarranging may include disposing the plates approximately parallel to oneanother. A yet further such embodiment may include the step of adaptingthe stack to permit flow of clean air within a first pair of plates, andcombustion gas within a pair of plates that may include only one of thefirst pair of plates. A still further embodiment may include the step ofadapting the stack to permit flow of clean air and combustion gasrespectively within alternating pairs of the plates in the stack.

Another such embodiment may further include the step of bending theplates in two or more locations. A further such embodiment may includecorrugating the plates. Yet a further such embodiment may include thestep of bending including bending the plates in a direction orthogonalto the flow of at least one of the two streams of fluid. In still afurther embodiment, the plates may comprise a material selected from agroup consisting of stainless steel, aluminum, galvanized steel, mildsteel, and aluminized steel.

In another such embodiment, the plates may include a plate metal. In afurther such embodiment, at least one of the streams may include astream of combustion gas. In yet a further such embodiment, at least oneof the streams may include a stream of clean air. In a still furtherembodiment, the fluid may include a fluid selected from a groupconsisting of a gas, a plasma, or a liquid. In yet another suchembodiment, further including the step of disposing the streams of fluidorthogonally to one another. In still another such embodiment, theplates may be secured by welding.

Another embodiment of the present invention may be a method includingproviding a fuel source, providing an air source, providing a combustionmechanism, disposing the combustion in a combustion chamber, adaptingthe combustion chamber to receive fuel from the fuel source and air fromthe air source, and to permit the operation of the combustion mechanism,providing a combustion gas channel, wherein the channel may include anenclosed stack of plates, and an exhaust pipe, and adapting the enclosedstack of plates to permit the flow of combustion gas between alternatingpairs, and clean air between the other pairs.

In an embodiment that includes the step of providing a combustion gaschannel, the embodiment may include the step of disposing the stack as astack of approximately parallel plates. Yet another such embodiment mayinclude the step of bending the plates in two or more locations. Afurther such embodiment may include the step of corrugating the plates.In still a further such embodiment, the step of bending may include thestep of bending the plates in a direction orthogonal to the flow of atleast one of the two streams of fluid.

In another such embodiment, the plates may comprise a material selectedfrom a group consisting of stainless steel, aluminum, galvanized steel,mild steel, and aluminized steel. In yet another such embodiment, theplates may include a plate metal. In yet another such embodiment, atleast one of the streams may include a stream of combustion gas. In afurther such embodiment, the fluid may include a fluid selected from agroup consisting of a gas, a plasma, or a liquid. Still a further suchembodiment may include the step of disposing the streams of fluidorthogonally to one another. In yet still another such embodiment, theplates may be secured by welding.

Another embodiment of the present invention may be an apparatuscomprising a combustion chamber, a source of electric power, a heaterexchanger, and a secondary containment tub surrounding at least the areabelow the combustion chamber, the source of electric power, and the heatexchanger, wherein the secondary containment tub is operative to preventliquid leakage. Thus, for example, a secondary containment tank may helpto prevent inadvertent leakage of fuels, antifreeze, and lubricants froma heat exchanger.

Another embodiment of the present invention may be an apparatus for afuel tank door comprising a hinged panel disposed to be swung between afirst position and a second position, the panel having at least a firstside and second side, wherein the first position is substantiallyvertical and the second position is more horizontal than the firstposition, wherein the first side of the panel is provided with fuelabsorbent pads, and wherein the first side of the panel may be shapedapproximately like a pan. A panel having a pan shape may have agenerally flat central portion substantially surrounded by a generallyelevated peripheral portion.

Another embodiment of the present invention may be an apparatuscomprising a heat exchanger for exchanging heat between combustiongasses and clean air, a combustion source, a fuel tank, a generator, andan air cooling system for the fuel tank and generator, wherein thecooling system uses air that is in a different stream from the cleanair. In such an arrangement, the cooling system may control thetemperature of the heater exclusive of the combustion and clean airstreams. Thus, the temperature of the fuel and the generator may beseparately controlled. This may be advantageous in certain conditions.For example, if the exterior temperature is −40 degrees Fahrenheit, thetemperature of the fuel may be maintained at about 60 degrees Fahrenheitby occasionally allowing outside air to cool the system. This may beaccomplished by occasionally using a fan to blow cold air from outsidethe system into the system, and by venting the system. The residual andradiant heat from the combustion chamber and heat exchanger may serve toheat the fuel and generator.

It is understood that both the foregoing general description and thefollowing detailed description are exemplary and explanatory only andare not restrictive of the invention as claimed. The accompanyingdrawings illustrating an embodiment of the invention and together withthe description serve to explain the principles of the invention.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a diagram illustrating a construction of an embodiment of alarge portable heater according to the present invention.

FIG. 2 is a flow diagram illustrating the method of heat exchangeemployed by an embodiment of the present invention.

FIG. 3 is a diagram of the present invention illustrating an embodimentof the present invention employing three plates.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

It is to be understood that the present invention is not limited to theparticular methodology, compounds, materials, manufacturing techniques,uses, and applications, described herein, as these may vary. It is alsoto be understood that the terminology used herein is used for thepurpose of describing particular embodiments only, and is not intendedto limit the scope of the present invention. It must be noted that asused herein and in the appended claims, the singular forms “a,” “an,”and “the” include the plural reference unless the context clearlydictates otherwise. Thus, for example, a reference to “a stream” is areference to one or more streams and includes equivalents thereof knownto those skilled in the art. In addition, as used here, the term“portable devices” includes moveable devices that may requiresignificant effort in moving, such as a heater with a 250 gallon fueltank. In general, portable is used as an antonym to a permanent fixture.

Unless defined otherwise, all technical and scientific terms used hereinhave the same meanings as commonly understood by one of ordinary skillin the art to which this invention belongs. Preferred methods,techniques, devices, and materials are described, although any methods,techniques, devices, or materials similar or equivalent to thosedescribed herein may be used in the practice or testing of the presentinvention. All references cited herein are incorporated by referenceherein in their entirety.

An object of the present invention is to provide, for example, a novellarge portable heater that has reduced susceptibility to hot spots.Another object of the present invention is to provide a heater that hasan increased life span. A further object of the present invention is toprovide a heater that permits very efficient heat transfer. Yet anotherobject of the present invention is to provide a heater that helps toprevent rust and corrosion.

The heat exchanger of the present invention may used with a variety offluids and in a variety of environmental applications, as demonstrated,for example, in the descriptions and explanations associated with thefigures below.

In one embodiment of the present invention, a heater may be constructed.This heater may include a combustion apparatus that may include a fuelsupply, an air supply, an igniter, and a chamber in which the combustionmay take place. In addition to the combustion apparatus, the heater mayalso contain a heat exchanger.

Certain embodiments of the present invention may also include certainsafety devices. For example, thermal sensors may be positioned atvarious points around the device to determine whether the device isremaining within the temperature range for which it was designed.Additionally, insulation or firewalls may be added to prevent heat frombeing unintentionally directed in specific directions, such as towards acontrol panel for the device. In certain embodiments, a layer offiberglass insulation may be placed around the firebox. Moreover, theclean air passages may surround the heat exchanger and combustionchamber. Such an arrangement may permit additional heat transfer to theclean air and may also help to insulate the combustion chamber and heatexchanger. One or more secondary containment tubs may be integrated intothe heater and may provide additional containment for any fluids(particularly fuels, lubricants, or antifreeze) that are used.

The fuel supply for the heater may be self-contained. In such anembodiment, the fuel supply may be equipped with a fuel porter forproviding fuel to a storage apparatus such as a fuel tank. In oneembodiment of the present invention, the fuel tank has a capacity ofabout 250 gallons. In other embodiments, the fuel tank may have acapacity that may range from about 50 gallons to about 1000 gallons. Thefuel tank may be equipped with a no-burp fill spout and drip pan. Such afill spout may be approximately 4 inches long.

One of the fuels that may be used in a heater according to the presentinvention is diesel. If diesel is used, it may be desirable to port thediesel exhaust into the firebox for a cleaner burn. Other fuels, such askerosene, propane, and butane, may also be used in the presentinvention. The design of the heat exchanger of the present invention isthus not dependent on the source of combustion gasses.

One embodiment of the present invention may be a heater that may becapable of providing about 700,000 BTU of hot air. This may have, as itscombustion source, a diesel engine. Such a diesel engine may, forexample, be a liquid cool diesel engine (such as a Kubota® D1105-EBGliquid cooled diesel engine (Kubota Corporation, Osaka, Japan)). Theengine may be provided with an approximately 20 gallon sump. In certainembodiments it may be desirable to include a sump with enhancedfiltration. Use of such a sump may provide the benefit of extending theaverage time between servicing the heater.

The firebox of the heater of the present invention may, for example, beconstructed from approximately 12 gauge 309 stainless steel. Wiring thatis used in conjunction with the present invention may, for example, beArctic Flex™ wire. Such wire, may, for example, provide wires with alayer of arctic grade PVC insulation within an arctic grade PVC sheath.Wires so insulated and sheathed may remain flexible at −20 degreesCelsius. The use of these materials may help the heater to last longerunder severe environmental conditions, by protecting the apparatus fromthe effects of cold and other weather phenomena.

Additionally, if a battery is used in connection with a heater accordingto the present invention, the battery may, for example, be a gel typebattery. Use of a gel type battery may provide the benefit of reducingthe risk of accidental release of battery acid into the system. Abattery may be included for a variety of reasons, including, forexample, to aid in starting the generator.

In certain portable embodiments, it may be desirable to place the heaterof the present invention on a chassis for easier transportation. Such achassis may, for example, be a heavy-duty chassis with a single axel anda trailer hitch.

In a particular embodiment, it may be advantageous to use anapproximately 12 gauge stainless steel firebox. Additionally, anapproximately 4,000 CFM blower may be of use in providing a largequantity of clean, warm air from a heater designed according to thepresent invention. In another embodiment, substitutable fuel nozzles maybe used to control the amount of fuel provided in the combustionchamber. In such an embodiment, the size of the nozzle may indirectlydetermine the temperature of the clean air.

A heater manufactured with a heat exchanger according to the presentinvention may be capable of producing a temperature rise of about 210degrees Fahrenheit above the ambient temperature. Additionally, a heateraccording to the present invention may be scaled to provide, forexample, between about 20,000 BTU and about 10,000,000 BTU.

A heater according to the present invention may incorporate a generator.Such a generator may for example, be a generator with a capacity in therange of about 8 kW to about 20 kW.

A heater according to the present invention may include a reactivethermostat. Such a thermostat may include a snap disk thermostat. Thesnap disk thermostat may operate to disable the burner in the combustionchamber when a certain temperature (for example, 300 degrees Fahrenheit)is reached. Additionally, in certain embodiments of the presentinvention, a thermostat may dynamically monitor the output temperatureof the clean air, and fire the burner at the appropriate times to keepthe temperature of the clean air in the approximate range of 170 degreesFahrenheit to 200 degrees Fahrenheit.

A heater exchanger according to the present invention may also be usedin other applications, such as heaters based on geothermal, nuclear, orsolar energy.

FIG. 1 provides a diagram of a design of a heater embodying an exampleof the present invention. In this example, combustion gases enter thestack of plates 110 from a first direction 120. These gases flowperpendicular to the folds in the plates. Thus, the gases experience aturbulent “washboard” effect. In contrast, the clean air enters in adirection 130 parallel to the folds in the plates. In such an embodimenta fan may be used to force the stream of clean air across the surface ofthe plates. In this embodiment the stack of plates has several folds orbends. This number is illustrative only, in other embodiments there maybe more or fewer. Additionally, the folds or bends may be replaced byconvexities or concavities.

The combustion gas may be generated in a combustion chamber 140. In thisexample the combustion gas is next provided to the stack of plates 110.Finally, the combustion gas is fed through a manifold 150 that maycontain devices such as filters to treat the combustion gas. Such amanifold 150 may, for example, be referred to as the exhaust stack. Acommercial air filter and noise muffler may, for example, be employed toreduce the potentially harmful side effects of releasing the combustiongasses.

Although it is not shown in this picture, in certain embodiments thatmay be employed indoors, the combustion gasses may be transported bypipe or other device to an external (e.g., outdoors) location.

After passing through the primary portion of the heat exchanger, theclean air may be directed through a shroud 160 back along the exteriorof the primary portion of the heat exchanger. This may permit the cleanair to capture additional heat by convection or radiation from the heatexchanger.

FIG. 2 depicts the method of heat exchange employed by an embodiment ofthe present invention. For example, in a first combustion step 210, fueland air may be combusted in a combustion chamber. In a second combustionstep 220, the gasses from the first combustion step 210 may be providedto one boundary of the heat exchanger 225. In a third combustion step230, the combustion gasses may be processed and exhausted. In certainembodiments, the combustion gasses may be at least partially recycled topermit a cleaner burn. Similarly, in a first ventilation step 240, cleanair is forced into the system using, for example, a fan. In a secondventilation step 250, the clean air is provided to another boundary ofthe heat exchanger 225. In the third ventilation step 260, the heatedclean air is vented to the area to be heated.

FIG. 3 is a diagram of the present invention illustrating an embodimentof the present invention employing three plates. In this embodiment, afirst stream of fluid, such as combustion gas, may enter from the sidethrough one or more first inputs 310. After passing through theapparatus the combustion gas may exit through one or more first outputs320. Similarly, a second stream of fluid, such as a clean air may enterthrough one or more second inputs 330 and may subsequently exit throughone or more second outputs 340. As shown in this figure, the directionof the flow of clean air and combustion gas may be approximatelyorthogonal to one another. The flows, however, may be prevented frommixing by plates 350. These plates 350 may be adapted to permit heattransfer as shown by the arrows, but may also be adapted to preventadmixture of clean air and combustion gas. Such plates 350, may, forexample, be fabricated from stainless steel or aluminized steel. Incertain embodiments, the plates may be bent. The plates may also bewelded to the enclosure 360 in which the heat exchange occurs.

Other embodiments of the invention will be apparent to those skilled inthe art from consideration of the specification and the practice of theinvention disclosed herein. It is intended that the specification andexamples be considered as exemplary only, with a true scope and spiritof the invention being indicated by the following claims.

1. A heat exchanger comprising an enclosure having at least one inputand at least one output for a first stream of fluid and at least oneinput and at least one output for a second stream of fluid, at leastthree plates secured within said enclosure, wherein said plates areadapted to prevent physical admixture of at least two streams of fluid,and wherein said plates are adapted to transfer heat from at least oneof said streams to at least one other of said streams.
 2. The heatexchanger of claim 1, wherein said plates are arranged in a stack. 3.The heat exchanger of claim 2, wherein said stack comprises a pluralityof approximately parallel plates.
 4. The heat exchanger of claim 2,wherein said stack is adapted to permit flow of clean air within a firstpair of plates, and combustion gas within a pair of plates that includesonly one of said first pair of plates.
 5. The heat exchanger of claim 2,wherein said stack is adapted to permit flow of clean air and combustiongas respectively within alternating pairs of said plates in said stack.6. The heat exchanger of claim 1, wherein said plates are bent in aplurality of locations.
 7. The heat exchanger of claim 6, wherein saidplates are bent in a direction orthogonal to the flow of at least one ofsaid two streams of fluid.
 8. The heat exchanger of claim 1, whereinsaid plates are corrugated.
 9. The heat exchanger of claim 1, whereinsaid plates comprise a material selected from a group consisting ofstainless steel, aluminum, galvanized steel, mild steel, and aluminizedsteel.
 10. The heat exchanger of claim 1, wherein said plates comprise aplate metal.
 11. The heat exchanger of claim 1, wherein at least one ofsaid streams comprises a stream of combustion gas.
 12. The heatexchanger of claim 1, wherein at least one of said streams comprises astream of clean air.
 13. The heat exchanger of claim 1, wherein saidfluid comprises a fluid selected from a group consisting of a gas, aplasma, or a liquid.
 14. The heat exchanger of claim 1, wherein saidstreams of fluid are disposed orthogonally to one another.
 15. Anapparatus comprising a fuel source, an air source, a combustionmechanism, a combustion chamber adapted to receive fuel from said fuelsource, air from said air source, and to contain an operative portion ofsaid combustion mechanism, and having an output for combustion gas aheat exchanger having an input connected to said output of saidcombustion chamber, wherein said heat exchanger comprises an enclosedstack of plates, said heat exchanger further having an input for cleanair, an output for clean air and an output for combustion gas, whereinsaid enclosed stack of plates comprises at least one first pair ofplates that permits the flow of combustion gas between said first pair,wherein said enclosed stack of plates comprises at least one second pairof plates that permits the flow of clean air between said second pair,and wherein at least one of said first pair and said second pair jointlyinclude a single plate.
 16. The apparatus of claim 15, wherein saidstack comprises a plurality of approximately parallel plates.
 17. Theapparatus of claim 15, wherein said plates are bent in a plurality oflocations.
 18. The apparatus of claim 17, wherein said plates are bentin a direction orthogonal to the flow of at least one of said combustiongas or said clean air.
 19. The apparatus of claim 15, wherein saidplates are corrugated.
 20. The apparatus of claim 15, wherein saidplates comprise a material selected from a group consisting of stainlesssteel, aluminum, galvanized steel, mild steel, and aluminized steel. 21.The apparatus of claim 15, wherein said plates comprise a plate metal.22. The apparatus of claim 15, wherein said combustion gas and saidclean air flow orthogonally to one another within said heat exchanger.23. The apparatus of claim 15, further comprising an exhaust pipeconnected to said combustion gas output of said heat exchanger.
 24. Amethod comprising providing at least three plates, disposing said platesto accommodate intra-plate flow of at least two streams of fluid,adapting said plates to prevent physical admixture of at least two ofsaid streams of fluid, and adapting said plates to transfer heat from atleast one of said streams to at least one other of said streams.
 25. Themethod of claim 24, wherein said step of disposing comprises arrangingsaid plates in a stack.
 26. The method of claim 25, wherein said step ofarranging comprises disposing said plates approximately parallel to oneanother.
 27. The method of claim 25, further comprising said step ofadapting said stack to permit flow of clean air within a first pair ofplates, and combustion gas within a pair of plates that includes onlyone of said first pair of plates.
 28. The method of claim 25, furthercomprising the step of adapting said stack to permit flow of clean airand combustion gas respectively within alternating pairs of said platesin said stack.
 29. The method of claim 24, further comprising the stepof bending said plates in a plurality of locations.
 30. The method ofclaim 29, wherein said step of bending comprising bending said plates ina direction orthogonal to the flow of at least one of said two streamsof fluid.
 31. The method of claim 24, further comprising corrugatingsaid plates.
 32. The method of claim 24, wherein said plates comprise amaterial selected from a group consisting of stainless steel, aluminum,galvanized steel, mild steel, and aluminized steel.
 33. The method ofclaim 24, wherein said plates comprise a plate metal.
 34. The method ofclaim 24, wherein at least one of said streams comprises a stream ofcombustion gas.
 35. The method of claim 24, wherein at least one of saidstreams comprises a stream of clean air.
 36. The method of claim 24,wherein said fluid comprises a fluid selected from a group consisting ofa gas, a plasma, or a liquid.
 37. The method of claim 24, furthercomprising the step of disposing said streams of fluid orthogonally toone another.
 38. The method of claim 24, wherein said plates are securedby welding.
 39. A method comprising providing a fuel source, providingan air source, providing a combustion mechanism, disposing at least anoperative portion of said combustion mechanism in a combustion chamberadapted to receive fuel from said fuel source, air from said air source,and having an output for combustion gases connecting a heat exchanger byan input to said output of said combustion chamber, wherein said heatexchanger comprises an enclosed stack of plates, providing said heatexchanger with an input for clean air, an output for clean air and anoutput for combustion gases, and adapting said enclosed stack of platesto permit the flow of combustion gas between alternating pairs, andclean air between the other pairs.
 40. The method of claim 39, whereinsaid stack of enclosed plates comprises a stack of approximatelyparallel plates.
 41. The method of claim 39, further comprising the stepof bending said plates in a plurality of locations.
 42. The method ofclaim 41, wherein said step of bending comprises bending said plates ina direction orthogonal to the flow of at least one of said two streamsof fluid.
 43. The method of claim 39, further comprising the step ofcorrugating said plates.
 44. The method of claim 39, wherein said platescomprise a material selected from a group consisting of stainless steel,aluminum, galvanized steel, mild steel, and aluminized steel.
 45. Themethod of claim 39, wherein said plates comprise a plate metal.
 46. Themethod of claim 39, wherein at least one of said streams comprises astream of combustion gas.
 47. The method of claim 39, wherein said fluidcomprises a fluid selected from a group consisting of a gas, a plasma,or a liquid.
 48. The method of claim 39, further comprising the step ofdisposing said streams of fluid orthogonally to one another.
 49. Themethod of claim 39, wherein said plates are secured by welding.
 50. Anapparatus comprising a combustion chamber, a source of electric powerelectrically connected to said combustion chamber, a heater exchanger,connected to an output of said combustion chamber and a secondarycontainment tub surrounding at least an area below said combustionchamber, said source of electric power, and said heat exchanger, whereinsaid secondary containment tub is operative to prevent liquid leakage.51. An apparatus for a fuel tank door comprising a hinged panel disposedto be swung between a first position and a second position, said panelhaving at least a first side and second side, wherein said firstposition is substantially vertical and said second position is morehorizontal than said first position, wherein said first side of saidpanel is provided with fuel absorbent pads, and wherein said first sideof said panel has an approximately pan shape.
 52. An apparatuscomprising a heat exchanger for exchanging heat between combustiongasses and clean air, a combustion source, connected to an input of saidheat exchanger a fuel tank, connected to an input of said combustionsource a generator electrically connected to said combustion source, andan air cooling system for said fuel tank and generator, electricallyconnected to said generator, wherein said cooling system uses air thatis in a different stream from said clean air.
 53. The heat exchanger ofclaim 1, wherein said heat exchanger is adapted to exchange heat in therange of about 20,000 BTU to about 10,000,000 BTU.
 54. The apparatus ofclaim 15, wherein said apparatus is adapted to provide warmth in therange of about 20,000 BTU to about 10,000,000 BTU.
 55. The method ofclaim of claim 24, further comprising adapting said plates to transferheat in the range of about 20,000 BTU to about 10,000,000 BTU.
 56. Anapparatus comprising at least three means for heat transfer, at leasttwo streams of fluid, wherein said at least three means for heattransfer are also physical admixture prevention means for preventingadmixture of at least two of said streams of fluid, and wherein saidmeans for heat transfer are adapted to transfer heat from at least oneof said streams to at least one other of said streams.
 57. The apparatusof claim 56, wherein said means for heat transfer are arranged in astack.
 58. The apparatus of claim 57, wherein said stack comprises aplurality of approximately parallel means for heat transfer.
 59. Theapparatus of claim 57, wherein said stack is adapted to permit flow ofclean air within a first pair of means for heat transfer, and combustiongas within a pair of means for heat transfer that includes only one ofsaid first pair of means for heat transfer.
 60. The apparatus of claim57, wherein said stack is adapted to permit flow of clean air andcombustion gas respectively within alternating pairs of said means forheat transfer in said stack.
 61. The apparatus of claim 56, wherein saidmeans for heat transfer are corrugated.
 62. The apparatus of claim 56,wherein said means for heat transfer are bent in a plurality oflocations.
 63. The apparatus of claim 62, wherein said means for heattransfer are bent in a direction orthogonal to the flow of at least oneof said two streams of fluid.
 64. The apparatus of claim 56, whereinsaid means for heat transfer comprise a material selected from a groupconsisting of stainless steel, aluminum, galvanized steel, mild steel,and aluminized steel.
 65. The apparatus of claim 56, wherein said meansfor heat transfer comprise a plate metal.
 66. The apparatus of claim 56,wherein at least one of said streams comprises a stream of combustiongas.
 67. The apparatus of claim 56, wherein at least one of said streamscomprises a stream of clean air.
 68. The apparatus of claim 56, whereinsaid fluid comprises a fluid selected from a group consisting of a gas,a plasma, or a liquid.
 69. The apparatus of claim 56, wherein saidstreams of fluid are disposed orthogonally to one another.